Question about the boosts

So I've been thinking about getting an XP boost so I can reach level 10 on Muriel (or any hero for that matter) at a pace faster than drying paint. Do they work for both profile level and hero level? Gotta make sure.

Side rant : I have 100 coins from profile level rewards and the 30 day boost costs 1200, 10$ is 1000 coins. RIP.